-issimus

-issimus lat. höchste Steigeung vgl. leicht + -este 'leichteste'

Via Proto-Italic *-isemos, from Proto-Indo-European *-is- (zero-grade of *-yōs (“intensive/comparative suffix”)) + *-tm̥mós (“absolute superlative suffix”). The latter is seen whole in -timus (e.g. intimus – extimus, citimus – ultimus, assimilated pessimus – optimus). The original form seems, however, to be *-m̥mós (cf. super – summus, Gothic 𐌹𐌽𐌽𐌿𐌼𐌰 (innuma, “innermost”)), with acquired t from the paradigm -ter- – -timus- (e.g. exter – extimus), and is cognate with Proto-Germanic *-umô (source, via metanalysis, of English -most). By various sound changes (e.g. *-isemos > *-ismos > -īmus) superlative grades in -īmus, -ēmus etc. (e.g. extrēmus, suprēmus) are also found.

The expected alteration of *-(o)ism̥mos to *-erimus is nowhere to be found. The -ss- may be an example of expressive lengthening of the *-s- or influence from specific forms as pessimus and endings in -errimus and -illimus.

Suffix

-issimus (feminine -issima, neuter -issimum); first/second-declension suffix

1. Added to an adjective noun to form its superlative grade:

   ‎altus (“high”) + ‎-issimus → ‎altissimus (“highest”)

   ‎fortis (“strong”) + ‎-issimus → ‎fortissimus (“strongest”)

Usage notes

• Stems in -ro- and -lo- instead take the suffix -errimus and -illimus respectively (e.g. *polkros (pulcher) > *polkrisemos > *polkr̥semos > *polkersimos > pulcherrimus).
• Some adjective nouns have irregular superlative grades from other roots or compositions (e.g. bonus – optimus, malus – pessimus, magnus – maximus).

Pronunciation

• (Classical) IPA^(key): /ˈis.si.mus/, [ˈɪs̠ːɪmʊs̠]
• (modern Italianate Ecclesiastical) IPA^(key): /ˈis.si.mus/, [ˈisːimus]

Declension

First/second-declension adjective.

Number	Singular				Plural
Case / Gender	Masculine	Feminine	Neuter		Masculine	Feminine	Neuter
Nominative	-issimus	-issima	-issimum		-issimī	-issimae	-issima
Genitive	-issimī	-issimae	-issimī		-issimōrum	-issimārum	-issimōrum
Dative	-issimō		-issimō		-issimīs
Accusative	-issimum	-issimam	-issimum		-issimōs	-issimās	-issima
Ablative	-issimō	-issimā	-issimō		-issimīs
Vocative	-issime	-issima	-issimum		-issimī	-issimae	-issima